Feminine writings usually have the word I written a thousand times. This is how you can tell the author was female, or at least had a feminine frame of mind while she was writing.
Male writings usually focus on others, or observed phenomenon. If there is a mix of both I’s and others, the writings are androgynous.
However, if the focus on others is gossipy seeming, focused on trivial social things or superficial things, it is usually feminine.